Class 31 Diesel at York

British Rail Class 31 Diesel Locomotive

Take a trip with the Brush Type 2 locomotive, designed for life on Britain’s regional railways in the 50s and 60s.

British Rail Class 31 Diesel Electric Locomotive

In the 1950’s the British Rail board at the time decided they needed to replace steam traction in the UK and to do this they needed to build large numbers of Diesel Locomotives and amongst the locos that were to be built was the Brush (Loughborough Locomotive Works) built class 30 later to be reclassified class 31 Locomotives.

Pilot Scheme

As what was to be called the Pilot scheme stage of introducing Diesel Locos throughout the UK a batch of 20 locos were ordered these were numbered D5500-D5519 (the D represented the fact the loco was a Diesel as simple as that).

These locos were built to an 80 mph maximum speed and were sent to the Eastern Region of British Rail to replace batch of steam locos although at least one member ventured to Scotland for trials on freight and passenger in the late 1950’s.


The locos really were quite unique and were pretty much restricted to the Eastern Region at Stratford Depot, East London for the whole of the sub classes working life which came to an end in the late 1970s, when a handful were converted to become heating units and taken into Departmental stock, they gained the nickname “Toffee Apples” this was conceived from the shape of the control key which was totally unique to this sub class of 20.

Many locos were built in the UK with a form of multiple working which enabled them to pull heavier loads if coupled to a similar loco with this type of facility, again the “Toffee Apple” was fairly unique in that it had a form of this equipment called red circle multiple working, this was denoted as such with a red circle above the buffers on each end of the loco. This meant that only locos with this type of equipment could work together on freight and passenger trains with only one driver present.

The sub class was built with steam heating boilers which meant they could operate on passenger trains which again were largely confined to the Eastern Region out of Liverpool Street, due to a lack of crew knowledge elsewhere.

Prototype D5500

Two of this small and unique, batch of locos survive today the prototype D5500 was preserved and donated to the National Railway Museum by British Rail and until the last few years had spent a number of years being made available in serviceable condition to be used by Preserved Organisations, visiting several during this period of time. The other loco is an anomaly as it was rebuilt after a serious accident as a standard loco with roof mounted Headcode panels and blue star coupling as well as being regeared to run at 90 mph. This loco formerly D5518 adopted the TOPS number 31101 in the late 1970s when British Rail first computerised its records and adopted a new system for numbering locos.

D5500-D5519 adopted the numbers 31001-31019 with the first built D5500 taking the number 31018 as vacated by D5518 after its rebuild.

Going back to the Class 30/31 story, as was the case with many pilot scheme engines it was decided that the locos would be re-engined and the original Mirrlees Power units replaced with a higher rated more powerful English Electric 12SVT engine rated at 1,470 bhp, these were to prove more successful and has prolonged the life of the class on Britains Railways with a handful still running today in 2011.

Production Batch

This brings us neatly on to the Production batch which numbered a further 243 examples, these were a continuation of the pilot scheme 20 locos albeit with different cab controls and the more standard Blue Star Multiple working, which can still be found on a number of other loco classes in the UK today, some of the loces were built as were all of the 31/0s with headcode discs as it was recognised that as steam disappeared this form of identifying the train would become obsolete they were fairly quickly replaced by Headcode boxes above the cabs this was by now becoming standard as loco classes were built in the UK.

The building of the 263 locos took 5 years to complete, the first 15 production locos were also delivered with a maximum speed of 80 mph with the remainder being 90 mph, the 80 mph batch were gradually refurbished along with the 90 mph batch in the 1980s and this speed was then corrected to be a standard 90 mph for all survivors at that time.

Eliminating Steam

These locos as delivered were used to gradually eliminate steam in certain areas, they had a low roué availability of 5 which meant they could visit every corner of the UK without class restriction although this really didn’t happen until the class was being run down and being re-deployed country wide by private operators and freight companies in the privatised UK railway scene.


Numbering wise in Pre TOPS days the fleet were numbered D5500-D5699 and D5800-D5862 with the introduction of TOPS 31001-31019, 31101-31327, 31400-31469 some of this batch were renumbered as 315XX when the ETH was isolated and they became freight engines, 31601-31602 these two locos were purely surrogate ETH fitted engines without an ETH Generator to enable them to work with an ETH engine either in multiple or in top and tail format which was introduced in the late 1990s by at least one private operator to work trains between Bedford and Bletchley and latterly Bristol-Weymouth and Brighton and was basically a safety feature to switch the ETH off remotely from a second engine in case of a fire breaking out on an un-crewed engine. Some locos also received departmental numbers 37203/97204 and latterly 31970 being seen on the main line over the years.

Steam Heat Boiler

The class were all built with steam heat boilers for working Passenger and Empty Coaching stock trains and would become common throughout the Eastern Region as well as being found on the Western Region, they could also be found on the Midland Region, however they were quite rare on the Scottish and Southern Regions unless a suitably trained crew from one of the other regions knew the route they were running on.

The class initially was built with Vacuum brakes which was the norm in those years and could work Passenger and freight trains albeit with load limitations, they certainly would have been used regularly on the whole of the Eastern region as part of the elimination of steam on passenger and freight trains swept across the UK railway network.

New Coaches

As new Coaches were built and new freight wagons ordered they were also fitted with air brakes to enable them to work with these new vehicles and they then became dual braked to enable them to become more flexible, also a batch of 24 locos initially were converted to have ETH (Electric Train Heat) during the 1970s this enabled this batch of locos to be used primarily to heat and move rakes of Empty Coaches between stations and depots and vice versa and to have them suitably heated for the forwarding loco to be attached. Although it wasn’t uncommon for these locos to be used on 90 or even 100 mph express trains with subsequent loss of timings if operating alone, whereas if two of the class were entrusted in a pair they could generally keep favourable timings on these express routes.


In to the 1980’s it was increasingly obvious that some of the early Multiple Unit classes would need replacing as a interim stop gap until “sprinterisation” a further batch of ETH fitted locos would be needed and during the last major overhauls the bulk of the class were to receive, what was to be classified a Heavy General Overhaul a further 44 locos were to receive ETH at Doncaster and these locos would then primarily be used on Cross Country passenger work between Liverpool and Hull and Cleethorpes and also between Birmingham and Norwich/Harwich. This was a useful stop gap and whilst the trains were usually between 4 and 6 coaches long these locos were ideal for this work.


As the railways geared up for “Sectorisation” leading on to Privatisation the locos were split into different “Pools” to enable them to be recognised as a Passenger, Parcels, Freight and Departmental sector loco, Boilers were being steadily isolated and even replaced by a concrete block in the boilers stead to enable the weight to be maintained and distributed evenly as built.


As more locos became surplus to requirements they were further deployed and the class suffered it’s first significant withdrawals being effectively “life expired” in to the 90s.

Ironically with the advent of sectorisation the number of available passenger locos of other classes fell and due to availability issues the 31 class could be found working more passenger trains than could have been envisaged. This was to last well in to the 1990s with seaside destination summer trains seeing regular visits such as Paignton/Skegness/Great Yarmouth and Blackpool.

A 'Versatile' Class

By now Sprinterisation had taken a firm hold and as most of the 1960s era Rolling stock had been replaced, less work was available although a couple of dozen locos were acquired by other operators in the “bold” new Privatised Railway, a small number were also retained by EWS (English/Welsh and Scottish Railways) for freight workings as they waited for new build Canadian class 66 locos to be delivered, the class had also gained for perhaps the first time since built a small amount of work around Hither Green Depot on the old Southern Region.

They really have been a versatile class and maybe not an absolute success story they have proved venerable and have been found from Mallaig to Penzance and Pwllheli to Great Yarmouth in a long Railway History of well over 50 years.

Several locos can be found preserved today and incredibly SERCO who operate Infrastructure Test Trains for Network Rail still operate a small fleet of locos on the Mainline and these can literally be found anywhere on the National Rail Network today.


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Class 31

Posted on Wednesday 12th September 2012 | 12:52 PM

Regarding workings on SR metals daily workings from Temple Mills to Hither Green were common place via West London Line and also Via Farringdon and London Bridge in the 1970s with banker provided as required Statford Crews never seemed to be in a hurry hoping to get Factory Jn Signalman to hold them till after the morning peak passenger traffic Hence a bit of overtime

david colvin

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